Multiple filament incandescent electric lamp



Oct. 15, 1940. e. B. DAVIS; JR

MULTIPLE FILAMENT INCANDESCENT ELECTRIC LAMP Filed June Patented Oct. 15,1940 1 UNITED STATES MULTIPLE FILAMENT INCANDESCENT ELECTRIC LAMP George B. Davis, Jr., Washington, D. 0. Application June 13, 1938, Serial No. 213,498

. 12 Claims.

This invention relates to an incandescent electric lamp having a plurality of filaments arranged so that upon the destruction of the active filament the lamp is not rendered useless, but, by the destruction of such active filament, another filament is automatically brought into circuit, thus continuing the lighting service of the globe.

The primary object of this invention is to provide a multiple filament incandescent lamp 110 with an automatic shunt circuit control mecha: nism of such rugged construction as to make it particularly adaptable to high-voltage series lighting, such as street lighting, where such a mechanism must serve to carry current sufiicient 15 to maintain not only the active filament lighting an individual globe but also the other lights in the series.

Another object of the present invention is to provide an incandescent lamp which will have go aplurality of filaments, one or more being held in reserve, so that upon the destruction of the active filament a rugged, but inexpensive, shunt mechanism located in the shell-cap of said lamp will automatically bring a reserve filament into g5 circuit.-

Another object is to provide a novel, practical, and efiicient means for automatically bringing into use a reserve filament in an incandescent lamp globe, having two or more filaments, upon 30 the breaking down or destruction of the preced-' ing active filament.

In this incandescent lamp one terminal of each of the multiple filaments is connected to a common conductor which extends down through the globe, and which makes direct connection with the screw-shell. The other ends of the filaments are individually connected with a spring contact mechanism located in the shell-cap, the points of said spring contacts being held apart by an insu- 40 lating fuse of any suitable material, such as oxidized copper or aluminum, which, upon the breaking down of the active filament, fuses through and establishes circuit to the next succeeding reserve filament.

In order that this invention may be more fully understood reference is here made to the accompanying drawing, in which:

Fig. l is a sectional view of the circuit control mechanism;

50 Fig. 2 is a sectional view of the globe and shellcap, showing the location of the control mechanism in relation thereto;

Fig. 3 shows the plane view of the insulating cover for such mechanism, and

55 Fig. 4 is acircuit diagram of the invention.

Fig. 1, at I and 2 are spring contacts that are mounted on support bar 3 by rivet, and insulated from thesame and from'each other by insulating washers 4, 5 and 6. The contact point 9 of spring-arm l is held from contact with bar 3 by 5 insulating member I. The contact point III of spring 2 is insulated from bar 3 by insulating member 8, these insulating members may be of oxidized metal, a strip of fiber insulation, or a coating of insulating varnish. Bar l3 serves as 10 a conductor from the base contact of the socket to spring I and also as a support for outer insulating sleeve cover l2. In the operation of this mechanism current entering 8J1. point l4 passes up bar l3 into the main filament which is connected with the mechanism at point l5. 0n the breaking down of the first filament there is an increase of voltage pressure across insulating member I, causing it to rupture, allowing spring I to establish circuit to first reserve filament which is connected with the mechanism at point I6. On the breaking down of the first reserve filament fuse 8 will rupture and current will pass to the second reserve filament which is connected at point I1.

Fig. 2 shows the location of the control mechanism in the shell-cap of the globe. In wiring the globe, temiinals l8, l9v and 20, leading in from the filaments, are connected with the mechanism as shown. Wire 2| is connected at point 22 and extends down through the base contact 23, and when the screw-shell 25 has been cemented in place, wire 2|, before it is soldered. at point 24, is used to draw the mechanism and connections thereto taut, leaving it suspended in the shell-cap thus preventing the shaking or shorting of the lead-in conductors. At 25 is shown the usual shell cap of an electric globe, and it is contemplated that the usual substance and means now used by manufacturers will be the substance and means employed to hold this in place. No claim is made to the shell cap, and it is shown in the drawing merely to indicate the position of the mechanism to which my invention relates.

Fig. 3 shows the plan view of the protecting insulating cover which slips over the mechanism.

Fig. 4 is the circuit diagram of the invention.

I claim:

1. A multiple filament incandescent lamp, comprising a main filament, a multiplicity of reserve filaments, leads to said filaments, insulation separating said leads, spring means electrically connected with said leads and pressing against said insulation.

2. A multiple filament incandescent lamp,

comprising a main filament, a multiplicity of reserve filaments, a common lead connecting one end of each of said filaments, separate leads connecting the other ends of said filaments with a multiplicity oil spring cut-out devices, said devices insulating said main filament from said reserve filaments, and said reserve filaments from. each other.

3. A multiple filament incandescent lamp comprising a main filament, a multiplicity of reserve filaments, a common lead connecting one end of each of said filaments, separate leads connecting the other ends of said filaments, insulation separating said leads from each other, spring circuit establishing means interposed between said leads and engaging under compression said insulation.

4. A multiple filament incandescent lamp, an operative filament, two reserve filaments, leads to said filaments, insulation separating said operative filament from said reserve filaments, insulation separating said reserve filaments, spring circuit establishing means electrically connected to said operative filament and engaging said insulation separating said operative filament from first reserve filament, spring circuit establishing means electrically connected to second reserve filament, said circuit establishing means engaging insulation separating said second reserve filament from first reserve filament.

5. An incandescent electric lamp comprising a main filament, two reserve filaments, leads to said filaments, insulation separating said leads, spring circuit establishing means connected to said first reserve filament and engaging insulation separating first reserve filament from main filament, spring circuit establishing means connected to second reserve filament and engaging insulation separating second reserve filament from first reserve filament.

6. A multiple filament incandescent lamp, an operative filament, two reserve filaments, a common lead connecting one endof each of said filaments, individual leads connecting the other end of said filaments, insulation separating said individual leads, spring circuit establishing means electrically connecting said first reserve filament and engaging the insulation separating said first reserve filament from the operative filament and also engaging the insulation separating the first reserve filament from the second reserve filament.

7. A multiple filament incandescent lamp, an operative filament, two reserve filaments, a common lead connecting one end of each of said filaments, individual leads connecting the other end of said filaments, insulation separating said operative filament from-said reserve filaments, insulation separating first reserve filament from the second reserve filament, spring circuit establishing means electrically connectedto the lead of said operative filament and engaging the insulation separating the operative filament from the first reserve filament, a spring circuit establishing means electrically connected to the lead of said first reserve filament and engaging the insulation separating first reserve filament from the second reserve filament.

8. A multiple filament lamp comprising an operative filament, a multiplicity of successively operative reserve filaments, a common lead connecting one end of each of said filaments, individual leads connecting the other ends of said filaments, insulation separating said operative filament leads from said reserve filaments, insulation separating the leads of said reserve filaments, spring circuit establishing means interposed between said individual-leads and engaging said separating insulation.

9. An incandescent lamp comprising an operative filament, a multiplicity of successively 0peratable reserve filaments; each of said successively operatabie reserve filaments being of higher lumens than the preceding filament; leads to said filaments, insulation separating said leads, spring circuit establishing means interposed between said leads and engaging said insulation.

10. An incandescent lamp having a main filament, a multiplicity of reserve filaments, leads to said filaments, insulation separating said leads,

spring circuit establishing means interposed between said leads and engaging said insulation.

11. A multiple filament incandescent lamp comprising a main filament, a multiplicity of reserve filaments, leads to said filaments, insulation separating said leads, spring contact means connected separately to each of said leads and engaging said insulation.

12. A multiple filament incandescent lamp, comprising a main filament, a multiplicity of reserve filaments, leads to said filaments, insulation separating said main filament leads from said reserve filaments leads, insulation separating each oi said reserve filaments leads, resilient means separately connected with one of the leads from each of said filaments and engaging said separating insulation.

GEORGE B. DAVIS, JR. 

